In order to support per-directory options for mod_perl6, I had to implement configuration merging, which I've been avoiding like the plague. But it's done, and it looks like this (some code omitted for brevity):

sub server_merge(%base, %new)
{
    my %merged;

    # merge handlers -- never inherit
    for @server_phases.map({$_ ~ '_handler'}) -> $h {
        %merged{$h} = %new{$h};
    }

    return %merged;
}

sub dir_merge(%base, %new)
{
    my %merged;

    # merge options -- inherit only if not set
    %merged = {};
    for %valid_options.keys -> $k {
        %merged{$k} = %new.exists($k) ??
            %new{$k} !! %base{$k};
    }

    # merge handlers -- never inherit
    for @dir_phases.map({$_ ~ '_handler'}) -> $h {
        %merged{$h} = %new{$h};
    }

    return %merged;
}

I still think it's cool that this is written in Perl 6. mod_parrot handles all the hard stuff behind the scenes so mod_perl6 code can stay lean and mean!